A typical example of conventional machines for shooting abrasives is disclosed in Japanese Patent No. 4085353. In that machine, the impeller comprises two side plates, i.e., a first side plate and a second side plate, and a plurality of blades. The impeller is mounted on the end of a rotating shaft. It is covered by a cover. The cover is protected by a liner that is divided into a plurality of pieces. The liner comprises a first-side liner component that is shaped as a trapezoidal plate. The first-side liner component is detachably secured by a screw to the side near the rotating shaft on the inner side of the cover. It has openings through which the first and second side plates pass. The liner also comprises a second-side liner component that is shaped as a trapezoidal plate. The second-side liner component is detachably secured by a screw to the side away from the rotating shaft on the inner side of the cover. It has openings through which the first and second side plates pass. The liner also comprises a front-side liner component that is U-shaped. The front-side liner component is installed between the front ends of the first- and second-side liners. The liner also comprises a rear-side liner component that is U-shaped. The second-side liner component is installed between the back ends of the first- and second-side liners. The liner also comprises a frame liner component that is shaped as an endless belt. The frame liner component is detachably placed around the upper ends of the first- and second-side liners and the front- and rear-side liners. The liner also comprises a ceiling-side liner component. The ceiling-side liner component has a looped projection formed on its lower surface. The looped projection is detachably inserted into the upper end of the frame liner component to cover the opening formed by the upper ends of the first- and second-side liners and the front- and rear-side liners. By configuring the liner as discussed above, the replacement of the liner components, which protect the cover for the impeller, becomes easier.